Hello Tomi,
based on the fact that Hungary was a part of Austrian-Hungarian Empire from 17th century untill 1918, the development of urban architecture in Budapest followed the same patterns as in Vienna, Prague and other cities of the empire. Of course, the castles, palaces, cathedrals and other unique buildings differ (anyway, it is not a matter of your dio - is it?) but the ordinary city houses are very similar.
Rural architecture is very unique in Hungary, especially in Puszta (Hungarian steppe).
Take a look at some examples of architecture at:
http://www.fsz.bme.hu/hungary/budapest/kepek/oldtimer.htm
Try the Google search for "Budapest", you will get much more.
HTH,
Petr